If I were to get a dirt cheap Chinese drone, would that be more likely to use RL or MCP? What’s the “standard”?

PID is more than enough to keep level. FPV relies on manual flight, but you can get Ardupilot for autonomous missions. There's no need for RL, nothing to gain here; level flight and following waypoints is a solved issue already.

And frankly as a pilot, I'd rather not see any completely autonomous drones with no oversight in the sky - that's one incident away in which blame cannot be put solely on the operator from getting the hobby completely banned.